52 The Philippine Journal of Science lais 



in terms of grams radium, Joly made certain assumptions, which, 

 as he states, are all on the side of reducing the final result. 

 Knoche ^° has also made something like thirty determinations 

 for a region in the Pacific Ocean off the coast of Chile and 

 obtained a mean value of 0.043 mache. 



Mialock ^^ has recently made some determinations of the radium 

 content of sea salt in the waters of the Atlantic and Pacific 

 Oceans. We have not been able to obtain access to his original 

 article, and our knowledge of his results is dependent on a brief 

 review appearing in the Chemical Abstracts. His results, how- 

 ever, seem to agree fairly well with those of Knoche. 



It is hard to account for the variation in the results of the 

 different investigators. One can easily assume that the radium 

 content varies considerably in different parts of the world, but 

 it is hardly to be expected that there should be a wide variation 

 in any given region. In measuring such minute quantities as 

 the radium in a few liters of sea water, errors in measurement 

 or method are inevitably large, but the large variation noted 

 cannot be accounted for on this basis. In order to get results 

 for widely separated regions that can be directly compared with 

 a fair degree of certainty, it is highly desirable that a standard- 

 ized method be adopted and even that a uniform type of instru- 

 ment be used whenever possible. 



EXPERIMENTAL RESULTS 



Thus far our determinations have been confined to one sample 

 of sea water from the China Sea. The sample was taken from 

 a depth of about 2 meters in the open sea at a distance of 

 approximately 8 kilometers from the entrance to Manila Bay. 

 About forty liters were collected in two large glass bottles, which 

 had been carefully cleaned. Thirty liters were then taken and 

 evaporated to 15 liters on the water bath, pure redistilled 

 hydrochloric acid being added from time to time, so that a slight 

 excess of acid was present during the entire process of concen- 

 tration. About 25 cubic centimeters of pure hydrochloric acid 

 were then added, and the entire quantity was sealed in a large 

 glass bottle. 



'° Bestimmungen des Emanationgehaltes im Meerwasser und der indu- 

 zierter Aktivitat der Luft zwischen der chilenischen Kiiste and der Oster- 

 insel, ibid. (1915), 13, 112-115. 



" Determination of the radioactive content of the salts in the waters of 

 the Atlantic and Pacific Oceans between Montevideo and El Callao, Anal. 

 Soc. dent. Argentina (1915), 79, 267-275. 



